That prompted McLaren to split with Honda, leaving it to rebuild its reputation in 2018 with Red Bull's junior outfit Toro Rosso and make enough progress to convince the senior team to make the switch from Renault for the coming season.
Honda's 2019 engine will be a further evolution of the new design it introduced back in 2017, as it believes it still has untapped potential from this concept as well as guaranteeing better reliability than another overhaul.
"We can carry over the current design, or concept, of PU," Honda F1 technical director Toyoharu Tanabe told Motorsport.com.
"We don't know exactly [what the limit is] because we haven't achieved a high level but we started with another concept and changed it for 2017.
"We learned something earlier, then changed it. In 2018, we carried over this concept and improved reliability and performance.
"At the moment we think this concept change is not wrong. It's suitable. Still we [intend to] carry over this concept and try to improve."
Despite recent reports suggesting Honda had discovered a new vibration problem when testing its 2019 engine, it is understood that the manufacturer has not experienced a major setback although is hoping to make more progress with the development before testing begins.
Convincing Red Bull to switch to Honda was a major result for the Japanese manufacturer after just one year with Toro Rosso.
As previously reported, the close relationship of the two Red Bull-owned teams will give Honda a technical boost as it prepares to supply two teams again – and it also helps validate the decision to keep the same engine idea.
"When you change the concept of the design a lot, it's very hard to get reliability," said Tanabe.
"It depends on the design level but I'm comfortable with carrying over our current concept. We have a new team, a new design of the car.
"It is a little bit easier to carry over that concept, because the detail is in the installation of the car.
"Toro Rosso and Red Bull, has communication and that's easier for the Red Bull side because Toro Rosso knows our power unit.
"They can communicate a problem or a kind of concern from the chassis point of view, and they can come back to us.
"If we have a completely new, or much updated design, it's much more work required."
Red Bull and Honda badges on the side of the Toro Rosso team truck
Photo by: Andrew Hone / LAT Images